On Thu, Jan 26, 2023 at 4:32 AM Siddhesh Poyarekar <siddh...@gotplt.org> wrote:
>
> Instead of using TREE_OPERAND (expr, 2) directly, use
> component_ref_field_offset instead, which does scaling for us. The
> function also substitutes PLACEHOLDER_EXPRs, which is probably what we
> want anyway but I'm not sure if it's relevant for tree-object-size.
OK. PLACEHOLDER_EXPR are only relevant pre simplification.
Thanks,
Richard.
> gcc/ChangeLog:
>
> PR tree-optimization/108522
> * tree-object-size.cc (compute_object_offset): Make EXPR
> argument non-const. Call component_ref_field_offset.
>
> gcc/testsuite/ChangeLog:
>
> PR tree-optimization/108522
> * gcc.dg/builtin-dynamic-object-size-0.c (DEFSTRUCT): New
> macro.
> (test_dynarray_struct_member_b, test_dynarray_struct_member_c,
> test_dynarray_struct_member_d,
> test_dynarray_struct_member_subobj_b,
> test_dynarray_struct_member_subobj_c,
> test_dynarray_struct_member_subobj_d): New tests.
> (main): Call them.
>
> Signed-off-by: Siddhesh Poyarekar <siddh...@gotplt.org>
> ---
> Testing:
> - Tested i686 to confirm that there are no new regressions
> - Tested x86_64 bootstrap and confirmed that there are no new
> regressions
> - ubsan config bootstrap in progress
>
> .../gcc.dg/builtin-dynamic-object-size-0.c | 81 +++++++++++++++++--
> gcc/tree-object-size.cc | 7 +-
> 2 files changed, 77 insertions(+), 11 deletions(-)
>
> diff --git a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
> b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
> index 569c0a87722..76079d8702e 100644
> --- a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
> +++ b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
> @@ -315,19 +315,70 @@ test_dynarray_struct_subobj2 (size_t sz, size_t off,
> size_t *objsz)
> }
>
> /* See pr #108522. */
> +
> +#define DEFSTRUCT(_s, _n) \
> + struct DS
> \
> + {
> \
> + char a[_n];
> \
> + unsigned long long b;
> \
> + int c;
> \
> + char d[2 * _n];
> \
> + } _s
> +
> size_t
> __attribute__ ((noinline))
> -test_dynarray_struct_member (size_t sz)
> +test_dynarray_struct_member_b (size_t sz)
> {
> - struct
> - {
> - char a[sz];
> - char b;
> - } s;
> + DEFSTRUCT (s, sz);
>
> return __builtin_dynamic_object_size (&s.b, 0);
> }
>
> +size_t
> +__attribute__ ((noinline))
> +test_dynarray_struct_member_c (size_t sz)
> +{
> + DEFSTRUCT (s, sz);
> +
> + return __builtin_dynamic_object_size (&s.c, 0);
> +}
> +
> +size_t
> +__attribute__ ((noinline))
> +test_dynarray_struct_member_d (size_t sz, size_t offset)
> +{
> + DEFSTRUCT (s, sz);
> +
> + return __builtin_dynamic_object_size (&s.d[offset], 0);
> +}
> +
> +size_t
> +__attribute__ ((noinline))
> +test_dynarray_struct_member_subobj_b (size_t sz)
> +{
> + DEFSTRUCT (s, sz);
> +
> + return __builtin_dynamic_object_size (&s.b, 1);
> +}
> +
> +size_t
> +__attribute__ ((noinline))
> +test_dynarray_struct_member_subobj_c (size_t sz)
> +{
> + DEFSTRUCT (s, sz);
> +
> + return __builtin_dynamic_object_size (&s.c, 1);
> +}
> +
> +size_t
> +__attribute__ ((noinline))
> +test_dynarray_struct_member_subobj_d (size_t sz, size_t offset)
> +{
> + DEFSTRUCT (s, sz);
> +
> + return __builtin_dynamic_object_size (&s.d[offset], 1);
> +}
> +
> size_t
> __attribute__ ((noinline))
> test_substring (size_t sz, size_t off)
> @@ -633,7 +684,23 @@ main (int argc, char **argv)
> if (test_dynarray_struct_subobj2 (42, 4, &objsz)
> != objsz - 4 - sizeof (long) - sizeof (int))
> FAIL ();
> - if (test_dynarray_struct_member (42) != sizeof (char))
> + DEFSTRUCT(ds, 64);
> + const size_t n = sizeof (ds.a);
> + if (test_dynarray_struct_member_b (n)
> + != sizeof (ds) - __builtin_offsetof (struct DS, b))
> + FAIL ();
> + if (test_dynarray_struct_member_c (n)
> + != sizeof (ds) - __builtin_offsetof (struct DS, c))
> + FAIL ();
> + if (test_dynarray_struct_member_d (n, 0)
> + != sizeof (ds) - __builtin_offsetof (struct DS, d))
> + FAIL ();
> + if (test_dynarray_struct_member_subobj_b (n) != sizeof (ds.b))
> + FAIL ();
> + if (test_dynarray_struct_member_subobj_c (n) != sizeof (ds.c))
> + FAIL ();
> + if (test_dynarray_struct_member_subobj_d (n, n - 2)
> + != sizeof (ds) - __builtin_offsetof (struct DS, d) - n + 2)
> FAIL ();
> if (test_substring_ptrplus (128, 4) != (128 - 4) * sizeof (int))
> FAIL ();
> diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
> index de93ffad9c9..9a936a91983 100644
> --- a/gcc/tree-object-size.cc
> +++ b/gcc/tree-object-size.cc
> @@ -56,7 +56,7 @@ struct GTY(()) object_size
> tree wholesize;
> };
>
> -static tree compute_object_offset (const_tree, const_tree);
> +static tree compute_object_offset (tree, const_tree);
> static bool addr_object_size (struct object_size_info *,
> const_tree, int, tree *, tree *t = NULL);
> static tree alloc_object_size (const gcall *, int);
> @@ -396,7 +396,7 @@ size_for_offset (tree sz, tree offset, tree wholesize =
> NULL_TREE)
> if unknown. */
>
> static tree
> -compute_object_offset (const_tree expr, const_tree var)
> +compute_object_offset (tree expr, const_tree var)
> {
> enum tree_code code = PLUS_EXPR;
> tree base, off, t;
> @@ -413,8 +413,7 @@ compute_object_offset (const_tree expr, const_tree var)
>
> t = TREE_OPERAND (expr, 1);
> off = size_binop (PLUS_EXPR,
> - (TREE_OPERAND (expr, 2) ? TREE_OPERAND (expr, 2)
> - : DECL_FIELD_OFFSET (t)),
> + component_ref_field_offset (expr),
> size_int (tree_to_uhwi (DECL_FIELD_BIT_OFFSET (t))
> / BITS_PER_UNIT));
> break;
> --
> 2.38.1
>
